Cronbach’s Coefficient Alpha
纠正了关于克朗巴赫α系数的六个常见误解，指出α不等于信度、高α不代表内部一致性等，并推荐在应用α前检验单维性和tau等价性假设，否则应使用基于结构方程模型的信度估计量。
This study disproves the following six common misconceptions about coefficient alpha: (a) Alpha was first developed by Cronbach. (b) Alpha equals reliability. (c) A high value of alpha is an indication of internal consistency. (d) Reliability will always be improved by deleting items using “alpha if item deleted.” (e) Alpha should be greater than or equal to .7 (or, alternatively, .8). (f) Alpha is the best choice among all published reliability coefficients. This study discusses the inaccuracy of each of these misconceptions and provides a correct statement. This study recommends that the assumptions of unidimensionality and tau-equivalency be examined before the application of alpha and that structural equation modeling (SEM)–based reliability estimators be substituted for alpha when one of these conditions is not satisfied. This study also provides formulas for SEM-based reliability estimators that do not rely on matrix notation and step-by-step explanations for the computation of SEM-based reliability estimates.